NOTES for Mat 7:3
Jesus' words about judgment could be seen as a continuation of a tradition going back to one of Israel's great teachers, Hillel, who said: do not judge your neighbor until you yourself have been in his place. Other teachers also thought that a righteous person should not rush to condemn his neighbor, even when, at least at first glance, there is something for which to condemn him. Jesus, however, appears to modify Hillel's saying somewhat: He says that before condemning a neighbor's sins, one must see one's own sin.
Of course, this counsel also has a spiritual and practical meaning: until you understand how to fight your own sins, you will not understand how to help your neighbor fight his. And it was understood as a matter of course that it made sense to look closely at a neighbor's sins only in order to help the neighbor get free of them. After all, in the Judaism of the Second Temple period, the generally accepted view of the Torah was that it was a guide on the path of righteousness and a means of fighting sin, not a kind of religious club with which to beat the sinner over the head for his sins.
In fact, Jesus calls for great caution in judging a person, not only in the sense of condemning him (no one would have thought of taking upon himself God's prerogative anyway), but in the sense of evaluating him as a sinner or a righteous person. Indeed, in order to give such an evaluation, one would have to know the human heart as only God can know it. Evaluating specific deeds and actions is another matter: anyone who knows the commandments and understands the essence of the matter being evaluated can assess them more or less adequately.
But the question of who is worthy of the Kingdom and salvation, and who is not, is not ours to decide, if only because we ourselves receive this Kingdom not because we are worthy of it. Besides, its story is still far from complete, and so the time for final evaluations has not yet come. And when it does come, in any case, we will not be the ones making them. Therefore our task is not evaluation, but the struggle against the sins that hinder us and our neighbors from walking the path of righteousness, so that we may complete this path in the Kingdom, where each of us will finally be freed from everything that prevents him from living life in its fullness.